Numerical Control Device and Program

The present invention relates to a numerical control device and a program.

Some numerical control devices that perform numerical control (NC) have a function called command point sequence compression. The command point sequence compression function is a function of compressing a command point sequence (hereinafter sometimes simply referred to as “point sequence”). That is, the command point sequence compression function is a function of interpolating a command path including a plurality of point sequences with a smaller number of straight lines or curves. Through use of the command point sequence compression function, a load of the numerical control device can be reduced. In this manner, the command point sequence compression function can suppress speed reduction to be caused by insufficient performance of the numerical control device.

Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2015-153097

In the conventional numerical control, the timing to execute an output command varies depending on each point sequence. Accordingly, when the point sequence is compressed, the number of timings at which the output command can be executed is reduced. As a result, in some cases, an accuracy of an operation such as machining performed by an industrial machine is decreased.

An object to be achieved by an embodiment of the present invention is to provide a numerical control device and a program that can prevent an accuracy of an operation such as machining from decreasing when a command point sequence is compressed.

A numerical control device of an embodiment includes a compressing unit, a calculating unit, and a holding unit. The compressing unit compresses a first command point sequence to create a second command point sequence. The calculating unit calculates an execution position of the operation in the second command point sequence, for a first output command that is held by the first command point sequence and instructs an industrial machine to execute the operation. The holding unit causes the second command point sequence to hold a second output command for instructing the industrial machine to execute the operation at the execution position.

The present invention can prevent the accuracy of the operation such as machining from decreasing when the command point sequence is compressed.

1 FIG. 1 1 1 100 200 Hereinafter, a numerical control system according to an embodiment is described with reference to the drawings. Note that, in each drawing used for the description of the embodiment below, in some case, scales of each portion are changed as appropriate. Further, in some cases, each drawing used for the description of the embodiment below is shown with a configuration being omitted for the sake of description. Further, throughout the drawings and the specification, the same reference symbols indicate similar elements. Further, in the drawings and in the specification and claims, a curve includes a straight line.is a block diagram illustrating an example of a numerical control systemaccording to the embodiment and main features of components included in the numerical control system. The numerical control systemincludes, as an example, a numerical control deviceand an industrial machine.

100 100 110 120 130 140 150 160 The numerical control deviceis a device that performs numerical control with respect to an industrial machine or the like. The numerical control deviceincludes, as an example, a processor, a ROM (read-only memory), a RAM (random-access memory), an auxiliary storage device, and a control interface. In addition, a busor the like connects those units.

110 100 110 110 110 110 100 120 140 110 110 110 111 112 113 114 115 The processoris a core part of a computer that performs processing such as calculation and control necessary for an operation of the numerical control device, and performs various types of calculation and processing. Examples of the processorinclude a CPU (central processing unit), an MPU (micro processing unit), an SoC (system on a chip), a DSP (digital signal processor), a GPU (graphics processing unit), an ASIC (application specific integrated circuit), a PLD (programmable logic device), and an FPGA (field-programmable gate array). As another example, the processoris a combination of a plurality of those units. Further, the processormay be a combination of those units with a hardware accelerator or the like. The processorcontrols the units to implement various functions of the numerical control devicebased on programs such as firmware, system software, and application software stored in the ROMor the auxiliary storage device. Further, the processorexecutes processing to be described later based on the program. Note that a part or the whole of the program may be incorporated in a circuit of the processor. The processorfunctions as, based on the program, as an example, a program analyzing unit, a point sequence compressing unit, an interpolation processing unit, a drive axis control unit, and an output control unit.

111 111 100 The program analyzing unitanalyzes the content of an NC program. Thus, the program analyzing unitidentifies what kind of operation and control the NC program causes the numerical control deviceto execute.

112 112 116 117 The point sequence compressing unitcompresses the point sequence. The point sequence compressing unitincludes, as an example, a command holding unitand an indicator calculating unit.

116 The command holding unitcauses a point sequence after compression to include an output command similar to that before compression

117 The indicator calculating unitcalculates an indicator I to be described later.

113 The interpolation processing unitcalculates an interpolation curve M to be described later.

114 200 The drive axis control unitcontrols, based on the NC program, the industrial machineto move along the point sequence.

115 200 The output control unitcontrols, based on the output command of the NC program, the industrial machineto execute an operation instructed by the output command.

120 130 110 120 120 120 110 130 130 110 130 The ROMand the RAMare main storage devices of the computer including the processoras a core. The ROMis a non-volatile memory that is exclusively used for readout of data. The ROMstores, for example, firmware or the like out of the above-mentioned programs. Further, the ROMalso stores data or the like to be used when the processorperforms various types of processing. The RAMis a memory used for reading and writing of data. The RAMis used as a work area or the like that stores data to be temporarily used when the processorperforms various types of processing. The RAMis typically a volatile memory.

140 110 140 140 140 110 110 The auxiliary storage deviceis an auxiliary storage device of the computer including the processoras a core. Examples of the auxiliary storage deviceinclude an EEPROM (electric erasable programmable read-only memory), an HDD (hard disk drive), and a flash memory. The auxiliary storage devicestores, for example, system software, application software, or the like out of the above-mentioned programs. Further, the auxiliary storage devicestores data to be used when the processorperforms various types of processing, data generated by the processing performed by the processor, various setting values, and the like.

140 200 1 1 1 0 NGX. S; Further, the auxiliary storage devicestores an NC program for controlling the industrial machine. A part of an example of the NC program before compression is shown below.

1 4 1 1 1000 0 200 200 In this NC program, one row indicates one operation. Nto Nindicate sequence numbers. Gindicates cutting feed. Xx (x is any numerical value) indicates movement by x millimeters in an X direction. Further, x is a numerical value for giving an instruction of a moving amount of a tool. Xindicates movement by 1 millimeter in the X direction. Ss (s is an integer of 0 or more) indicates a machining output command of laser. Further, s is a numerical value for giving an instruction of a power output value of the laser. Sindicates that power of 1,000 watts is output. Sindicates that power of 0 watt is output, that is, no laser is output. Note that a machining output command is an output command for instructing the industrial machineto perform machining. An output command is a command for instructing the industrial machineto perform any kind of operation. Each output command included in the NC program is an output command held by the NC program.

1 200 Thus, the first row (row of N) of this NC program indicates instructing the industrial machineto move by 1 millimeter in the X direction while performing laser machining. Further, in this NC program, the movement corresponding to one row indicates movement from an end point to a next end point included in a command path.

As described above, in the NC program, the output command can be output for each movement.

Some machining output commands give an instruction of gas cutting or electrical discharge machining other than laser machining.

150 100 200 100 200 150 The control interfaceis an interface for allowing the numerical control deviceto communicate with the industrial machineor the like. The numerical control devicecontrols the industrial machineor the like via the control interface.

160 100 The busincludes a control bus, an address bus, a data bus, and the like, and transmits signals to be transferred between the units of the numerical control device.

200 200 The industrial machineis a machine that operates based on numerical control. Examples of the industrial machineinclude a manipulator, a robot arm, a robot, and a machine tool. Examples of the machine tool include an NC lathe, an NC milling machine, a laser machining machine, a gas cutting machine, and an electrical discharge machining machine.

1 110 100 110 120 140 2 FIG. 2 FIG. 2 FIG. Hereinafter, the operation of the numerical control systemaccording to the embodiment is described with reference toand others. Note that the content of the processing in the operation description below is merely an example, and various types of processing that can obtain similar results can be used as appropriate.is a flowchart illustrating an example of processing performed by the processorof the numerical control device. The processorexecutes, for example, the processing ofbased on a program stored in the ROM, the auxiliary storage device, or the like.

11 110 100 110 110 100 100 140 110 100 110 110 110 11 12 2 FIG. In Step STof, the processorof the numerical control devicedetermines whether or not to compress the point sequence. The processordetermines to compress the point sequence when, for example, the processorhas received an input of an instruction to compress the point sequence. The input is input to the numerical control devicevia, for example, an input device. As another example, the instruction is input to the numerical control devicefrom another device. Further, for example, when the auxiliary storage deviceincludes an uncompressed NC program, the processordetermines to compress the point sequence for the NC program at a predetermined timing. Further, for example, when an NC program is input to the numerical control device, the processordetermines to compress the point sequence for the NC program. When the processordetermines not to compress the point sequence, the processormakes a determination of No in Step STand proceeds to Step ST.

12 110 200 110 110 200 100 100 110 200 110 110 12 11 110 11 12 110 In Step ST, the processordetermines whether or not to start the numerical control for the industrial machine. The processordetermines to start the numerical control when, for example, the processorhas received an input of an instruction to start the numerical control for the industrial machine. The input is input to the numerical control devicevia, for example, an input device. As another example, the instruction is input to the numerical control devicefrom another device. Further, for example, the processordetermines to start the numerical control for the industrial machineat a predetermined timing. When the processordetermines not to start the numerical control, the processormakes a determination of No in Step STand returns to Step ST. Thus, the processoris brought to a standby state of repeating Step STand Step STuntil the processordetermines to compress the point sequence or determines to start the numerical control.

110 110 11 12 110 11 13 When the processordetermines to compress the point sequence when the processoris in the standby state of Step STand Step ST, the processormakes a determination of Yes in Step STand proceeds to Step ST.

13 110 110 140 110 13 In Step ST, the processoracquires an NC program that is a target of the point sequence compression. The processoracquires the NC program from, for example, the auxiliary storage device. As another example, the processormay acquire the NC program from another device. Note that the NC program acquired in the most recent processing of Step STis hereinafter referred to as “acquired program”.

14 110 13 110 110 In Step ST, the processorcompresses the point sequence for the NC program acquired in Step ST. The processorcan use a publicly-known method as a method of compressing the point sequence. As an example, the processorcan use the compression method as described in Patent Document 1.

3 FIG. 4 FIG. 3 FIG. 3 FIG. 1 1 0 0 6 1 The point sequence before compression and the point sequence after compression are described with reference toand.is a diagram illustrating an example of a point sequence Sbefore compression. The point sequence Sis a command point sequence including (n+1) end points of an end point Pto an end point Pn. Here, n is a positive integer. Note thatillustrates only the end point Pto the end point Pout of the end points P of the point sequence S. Further, coordinates of an end point Pi and the component representation of a vector Pi are represented by (Xi, Yi).

3 FIG. Each curve Li between the end points inis a straight line connecting a point P(i−1) and a point Pi to each other. Here, i is an integer between 0 and n inclusive. Note that the curve between the end points may be a curve that is not a straight line.

Further, when the curve Li between the end points that is a straight line is represented by a vector, this straight line can be expressed by the following expression (1).

Note that the bold letter indicates a vector.

3 FIG. Note that the thick line in the curve L between the end points illustrated inindicates movement including an output command. A thin line in the curve L between the end points indicates movement including no output command.

4 FIG. 4 FIG. 4 FIG. 2 2 1 2 0 0 2 2 is a diagram illustrating an example of a point sequence Safter compression. The point sequence Sis a point sequence obtained by compressing the point sequence S. The point sequence Sis a command point sequence including (m+1) end points of an end point Qto an end point Qm. Here, m is an integer between 1 and n inclusive. Note thatillustrates only the end point Qto the end point Qout of the end points Q of the point sequence S. Further,also illustrates the end points P before compression.

2 0 2 0 1 2 1 2 5 1 2 3 5 2 3 FIG. 4 FIG. In the point sequence S, the number of point sequences is reduced from (n+1) to (m+1) through the compression of the point sequence. As is understood fromand, three end points P of the end point Pto the end point Pare compressed to two end points Q of the end point Qand the end point Q. That is, two curves L of a curve Li and a curve Lare compressed to one curve M. Further, four end points P of the end point Pto the end point Pare compressed to two end points Q of the end point Qand the end point Q. That is, three curves L of a curve Lto a curve Lare compressed to one curve M.

4 FIG. Each interpolation curve Mj inis a straight line connecting an end point Q(j−1) and an end point Qj to each other. Here, j is an integer between 0 and m inclusive. Note that the interpolation curve M may be a curve that is not a straight line.

Further, when the interpolation curve Mj that is a straight line is represented by a vector, this straight line can be expressed by the following expression (2).

1 2 1 2 Here, the interpolation curve Mj is an interpolation curve M obtained by compressing an end point Pkto an end point Pk. That is, the end point Pkis an end point matching the end point Q(j−1). Further, the end point Pkis an end point matching the end point Qj. In addition, (k2−k1) is the number of curves L between the end points before compression of the interpolation curve Mj. In other words, (k2−k1) is (“the number of end points before compression of the interpolation curve Mj”−1).

1 2 110 14 The point sequence before compression is an example of a first command point sequence. The point sequence Sis an example of the first command point sequence. The point sequence after compression is an example of a second command point sequence. The point sequence Sis an example of the second command point sequence. As described above, the processorperforms the processing of Step STto function as an example of a compressing unit that compresses the first command point sequence to create the second command point sequence.

15 110 In Step ST, the processorcalculates a compression ratio R of each interpolation curve M. The compression ratio R is a ratio of a length of an interpolation curve M to a sum of lengths of the curves L between the end points before compression of the interpolation curve M. Thus, a compression ratio Rj of the interpolation curve Mj can be obtained by, for example, the following expression (3).

Note that the expression (3) indicates the length of the curve L between the end points and the length of the interpolation curve M by norms of vectors.

110 1 The processorcalculates a compression ratio Rto a compression ratio Rm.

1 1 4 FIG. As an example, the compression ratio Rof the interpolation curve Minis obtained as the following expression (4).

16 110 In Step ST, the processorcalculates the indicator I of each curve L between the end points. The indicator I indicates a length (distance) of a section in which an operation instructed by an output command is executed. An indicator Ii of the curve Li between the end points can be obtained by, for example, the following expression (5).

R in the expression (5) is the compression ratio R of the interpolation curve M after compression of one or a plurality of curves between the end points including the curve Li between the end points.

110 1 The processorcalculates an indicator Ito an indicator In.

1 4 FIG. As an example, the indicator Iof the curve Li between the end points inis obtained as the following expression (6).

17 110 In Step ST, the processoradds an output command to the point sequence after compression. The output command added here is an output command for giving an instruction to perform the same operation as that instructed by the output command included in the acquired program. However, an execution position of the operation of the output command added here is, as described later, different from the output command included in the acquired program in. The addition of the output command causes the NC program to hold this output command.

The output command for giving an instruction to perform the operation executed in the curve Li between the end points is represented by an output command Ci. Further, the interpolation curve M after compression of the curve Li between the end points is represented by an interpolation curve Mj. Further, a start position of the operation instructed by the output command is represented by a position V(i−1), and an end position thereof is represented by a position Vi.

110 The processoradds each output command C to the point sequence after compression as an instruction to start the operation at the position V(i−1) and end the operation at the position Vi.

In the case of i=k1+1, the position V(i−1) is a position of a point Q(j−1).

In the case of i>k1+1, the position V(i−1) is a position advanced by a distance D(a−1) from the position of the point Q(j−1) along the interpolation curve Mj. The distance D(a−1) is expressed as follows.

In the case of i≠k2, the position Vi is a position advanced by a distance Da from the position of the point Q(j−1) along the interpolation curve Mj. The distance Da is expressed as follows.

As another example, the distance Da satisfies Da=D(a−1)+Ii.

In the case of i=k2, the position Vi is a position of a point Qj.

5 FIG. 5 FIG. 5 FIG. 2 1 3 5 0 1 1 2 3 3 4 5 5 2 4 is a diagram illustrating an example of a section in which an operation instructed by the output command is executed, in an example of the point sequence Safter compression.illustrates sections in which operations instructed by an output command C, an output command C, and an output command Care executed. A section from the position Vto the position Vis a section in which the operation instructed by the output command Cis executed. A section from the position Vto the position Vis a section in which the operation instructed by the output command Cis executed. A section from the position Vto the position Vis a section in which the operation instructed by the output command Cis executed. Note that, in the example of, the output command Cand the output command Care absent in the acquired program.

3 FIG. 3 FIG. 0 1 1 Further,illustrates the section in which the operation instructed by the output command is executed as well. In, a section from a point Pto a point P, that is, a section on a curve Li between the end points is a section in which the operation instructed by the output command Cis executed

2 3 3 3 4 5 5 5 A section from a point Pto a point P, that is, a section on a curve Lbetween the end points is a section in which the operation instructed by the output command Cis executed. A section from a point Pto a point P, that is, a section on a curve Lbetween the end points is a section in which the operation instructed by the output command Cis executed.

14 17 110 As described above, with the processing of Step STto Step ST, the processorconverts the acquired program into an NC program indicating the point sequence after compression.

110 16 17 110 17 As described above, the processorperforms the processing of Step STand Step STto function as an example of a calculating unit that calculates an execution position of the operation in the second command point sequence, for a first output command that is held by the first command point sequence and instructs the industrial machine to execute the operation. Further, the processorperforms the processing of Step STto function as an example of a holding unit that causes the second command point sequence to hold a second output command for instructing the industrial machine to execute the operation at the execution position.

18 110 14 17 140 110 110 11 18 In Step ST, the processorstores the NC program converted by the processing of Step STto Step STinto the auxiliary storage device. Further, the processormay delete or move the acquired program to prevent the acquired program from being erroneously executed. The processorreturns to Step STafter executing the processing of Step ST.

110 110 11 12 110 12 19 Meanwhile, when the processordetermines to start the numerical control when the processoris in the standby state of Step STand Step ST, the processormakes a determination of Yes in Step STand proceeds to Step ST.

19 110 200 18 In Step ST, the processoracquires the NC program to be executed. Which NC program is to be acquired is included in, for example, the input of instructing the industrial machineto start the numerical control. The NC program acquired here is, for example, the NC program stored in Step ST.

20 110 19 200 110 11 20 In Step ST, the processorexecutes the NC program acquired in Step STto perform numerical control of the industrial machine. The processorreturns to Step STafter executing the processing of Step ST.

1 100 100 According to the numerical control systemof the embodiment, the numerical control devicecompresses the point sequence. In this manner, the numerical control deviceof the embodiment can reduce the load.

1 100 100 100 100 Further, according to the numerical control systemof the embodiment, the numerical control devicecompresses the point sequence. Further, the numerical control deviceof the embodiment calculates the position V as a position at which the operation is executed in the point sequence after compression. This operation is an operation instructed by the output command held by the command point sequence before compression. Further, the numerical control deviceof the embodiment causes the command point sequence after compression to hold the command point sequence giving an instruction to execute the operation at a position based on the position V. In this manner, in the point sequence after compression, the number of times of the timing at which the output command can be executed is the same as that in the point sequence before compression. Accordingly, the numerical control deviceof the embodiment can prevent the accuracy of the operation such as machining from decreasing when the point sequence is compressed.

1 100 100 Further, according to the numerical control systemof the embodiment, the numerical control devicedefines the position V at which the operation is executed by using a length. In this manner, the numerical control deviceof the embodiment can set the position V not only to an end point but also to a position between an end point and an end point.

1 100 200 Further, according to the numerical control systemof the embodiment, examples of the operation instructed by the output command include laser machining, gas cutting, and electrical discharge machining. Thus, the numerical control deviceof the embodiment can cause the industrial machineto execute laser machining, gas cutting, electrical discharge machining, or the like.

100 0 The above-mentioned embodiment can be modified as follows. In the above-mentioned embodiment, the indicator Ii is a distance of movement from the position V(i−1) to the position Vi along the interpolation curve M. However, the numerical control devicemay use, in place thereof, an indicator Ii indicating a distance of movement from a different position to the position Vi. The different position is, for example, the point Q(j−1), the point Q, or the like.

In the above-mentioned embodiment, the position V is defined by using the length. Further, in the above-mentioned embodiment, the indicator I indicates a length. However, the position V may be defined by using something other than the length, such as time, coordinates, a ratio, or the like. Further, the indicator I may indicate something other than the length, such as time, coordinates, a ratio, or the like. The following cases (α1) to (α4) represent examples of cases in which the position V is defined by using something other than the length. However, description of parts similar to the above-mentioned embodiment is basically omitted.

110 110 A time required for movement from the point P(i−1) to the point Pi is represented by Ti. A time required for movement from the point Q(j−1) to the point Qj is represented by Uj. The processoruses the time Ti in place of the length of the curve Li between the end points in the expression (3) and the expression (4). Further, the processoruses the time Uj in place of the length of the interpolation curve Mj in the expression (3).

110 In (α1), the indicator I indicates a length of the time required for advancing the section in which the operation instructed by the output command is executed. The processoruses, in (α1), a time E(a−1) and a time Ea in place of the distance D(a−1) and the distance Da. Thus, in the case of i>k1+1, the position V(i−1) is a position advanced from the position of the point Q(j−1) along the interpolation curve Mj until the time E(a−1) elapses. In the case of i≠k2, the position Vi is a position advanced from the position of the point Q(j−1) along the interpolation curve Mj until the time Ea elapses.

(α2) Case 2 in which the Position V is Defined by Using Time

110 Unlike (α1), the processorobtains the compression ratio R similarly to the above-mentioned embodiment. Other points are similar to (α1).

(α3) Case in which the Position V is Defined by Using a Ratio

In the case of i>k1+1, the position V(i−1) is a position advanced by (a ratio F(a−1) of the length of the interpolation curve Mj) (=Mj×F(a−1)) from the position of the point Q(j−1) along the interpolation curve Mj. The ratio F(a−1) is (a sum of the lengths from a curve L(k1+1) between the end points to a curve L(i−1) between the end points) corresponding to (a sum of the lengths of the curves L between the end points before compression of the interpolation curve Mj). That is, the following is satisfied.

In the case of i≠k2, the position Vi is a position advanced by (a ratio Fa of the length of the interpolation curve Mj) (=Mj×Fa) from the position of the point Q(j−1) along the interpolation curve Mj. The ratio Fa is (a sum of the lengths from the curve L(k1+1) between the end points to the curve Li between the end points) corresponding to (a sum of the lengths of the curves L between the end points before compression of the interpolation curve Mj). That is, the following is satisfied.

Note that the ratio F is a type of the indicator I, and is an indicator I indicating the ratio.(α4) Case in which the Position V is Defined by Using Coordinates

A position closest to the point P(i−1) on the interpolation curve Mj is represented by a position V(i−1). A position closest to the point Pi on the interpolation curve Mj is represented by a position Vi. The coordinates of the position V(i−1) are represented by (XV(i−1), YV(i−1)), and the coordinates of the position Vi are represented by (XVi, YVi). The coordinates (XV(i−1), YV(i−1)) and the coordinates (XVi, YVi) are types of the indicator I, and are indicators I indicating the coordinates.

1 100 100 As described above, according to the numerical control systemof the embodiment, the numerical control devicedefines the position V at which the operation is executed by using the time, the coordinates, the ratio, or the like, other than the length. In this manner, the numerical control deviceof the embodiment can set the position V not only to an end point but also to a position between an end point and an end point.

110 The processormay implement a part or the whole of the processing executed by the program in the above-mentioned embodiment by a hardware configuration of a circuit.

The program for implementing the processing of the embodiment is, for example, transferred in a state of being stored in a device. However, this device may be transferred in a state of not storing the program. In addition, the program may be separately transferred and may be written into the device. The transfer of the program at this time can be achieved by, for example, storing the program into a removable storage medium or downloading the program via a network such as the Internet or a LAN (local area network).

An embodiment of the present invention has been described above, but the embodiment is described as an example and does not limit the scope of the present invention. The embodiment of the present invention can be embodied in various modes without departing from the gist of the present invention.

1 numerical control system 100 numerical control device 110 processor 111 program analyzing unit 112 point sequence compressing unit 113 interpolation processing unit 114 drive axis control unit 115 output control unit 116 command holding unit 117 indicator calculating unit 120 ROM 130 RAM 140 auxiliary storage device 150 control interface 160 bus 200 industrial machine